Wearable cardiac monitor

ABSTRACT

Systems, methods and devices for reducing noise in cardiac monitoring including wearable monitoring devices having at least one electrode for cardiac monitoring; in some implementations, the wearable device using a composite adhesive having at least one conductive portion applied adjacent the electrode; and, in some implementations, including circuitry adaptations for the at least one electrode to act as a proxy driven right leg electrode.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This is a nonprovisional application claiming the benefit of andpriority to the provisional application, U.S. 61/710,768 filed Oct. 7,2012, the entire contents, teachings and suggestions thereof beingincorporated herein by this reference as if fully set forth here.

BACKGROUND

Advances in electronics, sensor technology and materials science haverevolutionized patient monitoring technologies. In particular, manylight and wearable devices are becoming available for a variety ofcardiac monitoring applications. However, improvements may yet bedesired for robust wearable devices that provide effective datacollection, in some cases also with increased patient convenience andcomfort. Other alternatives may include developments in one or more ofdevice attachment, size, flexibility, data transfer, among others.

Further alternatives for cardiac patients and their physicians may theninclude robust and convenient personal cardiac monitors that in someinstances may collect and transfer long-term data as well as monitorevents in real-time.

SUMMARY

Described herein are several medical monitoring devices and systems, insome instances for long-term sensing and/or recording of cardiac patientdata. A number of alternative implementations and applications aresummarized and/or exemplified herein below and throughout thisspecification.

These as well as other aspects are exemplified in a number ofillustrated alternative implementations and applications, some of whichare shown in the figures and characterized in the claims section thatfollows. However, as will be understood by the ordinarily skilledartisan, the above summary and the detailed description below do notdescribe the entire scope of the inventions hereof and are indeed notintended to describe each illustrated embodiment or every implementationof the present inventions nor provide any limitation on the claims orscope of protection herein set forth below.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings include:

FIG. 1, which includes sub-part FIGS. 1A-1G, illustrates severalalternatives of the present inventions, including various of isometric,top and bottom plan and elevational views of devices and alternativeconductive adhesive structures.

FIG. 2, which includes sub-part FIGS. 2A-2C, provides circuit diagramsof alternatives to a driven right leg circuit.

FIG. 3 is a flow chart including alternative methods of use.

FIG. 4 illustrates an exemplary computer system or computing resourceswith which implementations hereof may be utilized.

FIG. 5, which includes sub-part FIGS. 5A-5D, provides alternativescreenshots of alternative software implementations according hereto.

DETAILED DESCRIPTION

While the inventions hereof amenable to various modifications andalternative forms, specifics thereof have been shown by way of examplein the drawings and the following description. It should be understood,however, that the intention is not to limit the invention to theparticular embodiments described. The intention is to cover allmodifications, equivalents, and alternatives falling within the spiritand scope of the invention whether described here or otherwise beingsufficiently appreciable as included herewithin even if beyond theliteral words hereof.

In one aspect, a system hereof may include a device for monitoringphysiological parameters such as one or more or all of electrocardiogram(aka ECG or EKG), photoplethysmogram (aka PPG), pulse oximetry and/orpatient acceleration or movement signals. Systems hereof may beestablished to measure and process such signals of a patient using orincluding one or more of the following elements: (a) a circuit,sometimes flexible, embedded in a flat elastic substrate having a topsurface and a bottom surface, the circuit having (i) at least one sensormounted in or adjacent the bottom surface of the flat elastic substrate,the at least one sensor being capable of electrical or opticalcommunication with the patient, (ii) at least one signal processingmodule for receiving and/or accepting signals from the at least onesensor in some implementations also providing for transforming suchsignals for storage as patient data; (iii) at least one memory modulefor receiving and/or accepting and storing patient data, (iv) at leastone data communication module for transferring stored patient data to anexternal device, and (v) a control module for controlling the timing andoperation of the at least one sensor, one or more of the at least onesignal processing module, the at least one memory module, the at leastone data communication module, and/or the control module capable ofreceiving commands to implement transfer of patient data by the at leastone data communication module and to erase and/or wipe patient data fromthe at least one memory module; and (b) a anisotropically conductiveadhesive removably attached to the bottom surface of the flat elasticsubstrate, the anisotropically conductive adhesive capable of adheringto skin of the patient and of conducting an electrical signalsubstantially only in a direction perpendicular to the bottom surface ofthe flat elastic substrate, and/or in some implementations including aconductive portion adjacent the sensor or sensors and a non-conductiveportion.

In some implementations, devices hereof will be for comprehensivelong-term cardiac monitoring. Features of such may include one or moreof a Lead 1 ECG, PPG, pulse oximeter, accelerometer, and a button orother indicator for manual patient event marking. Such a device may beadapted to store up to, for example, about two weeks of continuous data(though more will also be feasible in alternative implementations),which may in some implementations be downloaded to a clinic or othercomputer in a short time period, as for one example, in only about 90seconds (though less time will be viable in alternative implementations)via computer connection, whether wireless or wired as in one example byUSB or other acceptable data connection. A companion software dataanalysis package may be adapted to provide automated event captureand/or allow immediate, local data interpretation.

Intermittent cardiac anomalies are often difficult for physicians todetect and/or diagnose, as they would typically have to occur during aphysical examination of the patient. A device hereof may address thisproblem with what in some implementations may be a continuous orsubstantially continuous monitoring of a number of vital signs.

Some alternative features may include (i) a driven “Right Leg” circuitwith electrodes located only on the chest, (ii) a “z-Axis” oranisotropic conductive adhesive electrode interface that may permitelectrical communication only between an electrode and a patient's skinimmediately beneath the electrode, (iii) data transmission to andinterpretation by a local computer accessible to CCU/ICU personnel, (iv)a unique combination of hardware allows correlation of multiple datasources in time concordance to aid in diagnosis.

In some alternative implementations, devices and systems hereof mayprovide 1) reusability (in some cases near or greater than about 1000patients) allows recouping cost of the device in just about 10-15patient tests, 2) one or more of ecg waveform data, inertial exertionsensing, manual event marking, and/or pulse oximeter, any or all ofwhich in time concordance to better detect and analyze arrhythmicevents, 3) efficient watertightness or waterproofing (the patient caneven swim while wearing the device), and 4) a comprehensive analysispackage for immediate, local data interpretation. An alternative devicemay be adapted to take advantage of flex-circuit technology, to providea device that is light-weight, thin, durable, and flexible to conform tothe patient's skin.

FIGS. 1 and 2 illustrate examples of alternative implementations ofdevices that may be so adapted.

FIG. 1 shows a device 100 that has a component side or top side 101,patient side or circuit side 102, and one or more inner electricallayer(s), generally identified by the reference 103 and an elongatedstrip layer 105. The strip layer 105 may have electronics thereon and/ortherewithin. FIG. 1A shows isometrically these together with some otherelements that may be used herewith. FIG. 1B is more specificallydirected to a top side 101 plan view and FIG. 1C to an underside,patient side 102 plan view and FIG. 1D a first elevational, side view.

Many of the electronics hereof may be disposed in the electronics layeror layers 103, and as generally indicated here, the electronics may beencapsulated in a material 104 (see FIGS. 1A, 1B and 1D for someexamples), plastic or the like, or potting material, to fix them inoperative position on or in or otherwise functionally disposed relativeto the elongated strip layer 105. The potting or other material may inmany implementations also or alternatively provide a waterproof orwatertight or water resistant coverage of the electronics to keep themoperative even in water or sweat usage environments. One or more accesspoints, junctions or other functional units 106 may be provided onand/or through any side of the encapsulation material 104 for exterioraccess and/or communication with the electronics disposed therewithin,or thereunder. FIGS. 1A, 1B and 1D show four such accesses 106 on thetop side. These may include high Z data communication ports and/orcharging contacts, inter alia. This upper or component side 101 ofdevice 100 may be coated in a silicone compound for protection and/orwaterproofing, with only, in some examples, a HS USB connector exposedvia one or more ports 106, e.g., for data communication or transferand/or for charging.

The elongated strip layer 105 may be or may include a circuit or circuitportions such as electrical leads or other inner layer conductors, e.g.,leads 107 shown in FIG. 1D, for communication between the electronics103 and the electrically conductive pads or contacts 108, 109 and 110described further below (108 and 109 being in some examples, highimpedance/high Z silver or copper/silver electrodes forelectrocardiograph, ECG, and 110 at times being a reference electrode).In many implementations, the strip layer 105 may be or may include flexcircuitry understood to provide acceptable deformation, twisting,bending and the like, and yet retain robust electrical circuitryconnections therewithin. Note, though the electronics 103 and electrodes108, 109, 110 are shown attached to layer 105; on top for electronics103, and to the bottom or patient side for electrodes 108, 109, 110; itmay be that such elements may be formed in or otherwise disposed withinthe layer 105, or at least be relatively indistinguishably disposed inrelative operational positions in one or more layers with or adjacentlayer 105 in practice. Similarly, the leads or traces 107 are shownembedded (by dashed line representation in FIG. 1D); however, these maybe on the top or bottom side, though more likely top side to insulatefrom other skin side electrical communications. If initially top side(or bottom), the traces may be subsequently covered with an insulativeencapsulant or like protective cover (not separately shown), in manyimplementations, a flexible material to maintain a flexible alternativefor the entire, or majority of layer 105.

On the patient side 102, the ECG electrodes 108, 109 and 110 may be leftexposed for substantially direct patient skin contact (though likelywith at least a conductive gel applied therebetween); and/or, in manyimplementations, the patient side electrodes 108, 109 and/or 110 may becovered by a conductive adhesive material as will be described below.The electrodes may be or may be may be plated with a robust highconductive material, as for example, silver/silver chloride forbiocompatibility and high signal quality, and in some implementationsmay be highly robust and, for one non-limiting example, be adapted towithstand over about 1000 alcohol cleaning cycles between patients.Windows or other communication channels or openings 111, 112 may beprovided for a pulse oximeter, for example, for LEDs and a sensor. Suchopenings 111, 112 would typically be disposed for optimum lightcommunication to and from the patient skin. An alternative dispositionof one or more light conduits 111 a/112 a is shown in a non-limitingexample in FIG. 1D more nearly disposed and/or connected to theelectronics 103. A variety of alternative placements may be usableherein/herewith.

FIG. 1D provides a first example of an adhesive 113 that may be usedherewith. The adhesive layer 113 is here a double-sided adhesive forapplication to the bottom side 102 of the device 100, and a second side,perhaps with a different type of adhesive for adhering to the skin ofthe human patient (not shown). Different types of materials for adhesionmight be used in that the material of choice to which the adhesive layeris to be attached are different; typically, circuit or circuit boardmaterial for connection to the device 100, and patient skin (notseparately shown) on the patient side. A protective backing 114 may beemployed on the patient side until application to the patient isdesired. Note, in many applications, the adhesive 113 is anisotropic inthat it may preferably be only conductive in a single or substantially asingle direction, e.g., the axis perpendicular to the surface ofadhesive contact. Thus, good electrically conductive contact for signalcommunication can be had through such adhesive to/through the adhesiveto the electrical contacts or electrodes, 108, 109 and 110. Note, acorresponding one or more light apertures 111 b/112 b are shown in theadhesive of 113 of the example of FIG. 1D to communicate lighttherethrough in cooperation with the light conduit(s) 111 a/112 ain/through layer 105 for communication of light data typically involvedin pulse oximetry.

The adhesive may thus be placed or disposed on the device 100, in someimplementations substantially permanently, or with some replaceability.In some implementations, the device as shown in FIGS. 1A-1D and/or 1Gwithout (or with in some implementations) the adhesive may be reusable.In many such cases, the adhesive layer 113 may be removed and replacedbefore each subsequent use, though subsequent re-use of and with a layer113 is not foreclosed. In a first or subsequent use with a replaceableadhesive layer 113, it may be that the user applying the device to thepatient, e.g., the physician or technician or even the patient,him/herself, applies the conductive transfer adhesive 113 to the patientside 102 of the device 100. The protective backing 114 may then beremoved, and the device adhered to the patient and activated. Activationmay occur in a number of ways; in some, it may be pre-set that anaffirmative activation interaction may not be necessary from the doctoror patient or like due to either an inertial and/or a pulse oximeteractivation which may be substantially automatically activating, e.g.,upon receiving sufficient minimum input (movement in case of inertialsystem or light reflection of blood flow for pulse oximetry); however, abutton may be provided at access 106 or in some other location adjacentthe electronics to allow the patient to start or stop the device orotherwise mark an event if desired. In one exemplar implementation thedevice may be worn for a period such as two weeks for collection of datasubstantially continuously, or at intervals as may be preferred andestablished in or by the systems hereof.

After a monitoring period is over a physician, technician, patient orother person may then remove the device from the patient body, removethe adhesive, in some instances with alcohol, and may establish a datacommunication connection for data transfer, e.g., by wirelesscommunication or by insertion/connection of a USB or like data connectorto download the data. The data may then be processed and/or interpretedand in many instances, interpreted immediately if desired. A powersource on board may include a battery and this can then also bere-charged between uses, in some implementations, fully rechargedquickly as within about 24 hours, after which the device could then beconsidered ready for the next patient.

Some alternative conductive adhesives may be used herewith. FIGS. 1E, 1Fand 1G show one such alternative conductive adhesive 113 a; a bottomplan view in FIG. 1E and elevational side views thereof in FIGS. 1F and1G (as being connected to a device 100 in FIG. 1G). In someimplementations, the conductivity may be anisotropic as introducedabove; in some conductive primarily if not entirely in the direction ofthe Z-Axis; perpendicular to the page (into and/or out of the page) inFIG. 1E, and/or vertically or transversally relative to the longhorizontal shown axis of device 100 in the implementation view of FIG.1F.

The implementation of this particular example includes a compositeadhesive 113 a which itself may include some non-conductive portion(s)113 b and some one or more conductive portions 113 c. The adhesivecomposite 113 a may, as described for adhesive 113 above be double sidedsuch that one side adheres to the patient while the other side wouldadhere to the underside 102 of the device 100 (see FIG. 1G) so that oneor more conductive portions 113 c may be disposed or placed inelectrically communicative and/or conductive contact with the integratedelectrodes on the electronic monitoring device 100. Since the electrodeswould operate better where they may be electrically isolated orinsulated from each other, yet each making electrical contact orcommunication with the patient's skin, the adhesive may further be morespecifically disposed in some implementations as follows.

As shown in FIGS. 1E and 1F, three isolated conductive portions 113 cmay be disposed separated from each other by a body portion 113 b whichmay be non-conductive. These could then correspond to the electrodes108, 109, 110 from the above-described examples, and as moreparticularly shown schematically in FIG. 1G (note the scale isexaggerated for the adhesive 113 a and thus, exact matching to theelectrodes of device 100 is not necessarily shown). In some examples,the electrode areas 113 c may be a conductive hydrogel that may or maynot be adhesive, and in some examples, may be made of a conductive anadhesive conductive material such as 3M Corporation 9880 Hydrogeladhesive (3M Company, St. Paul, Minn.). These areas 113 c may then beisolated from each other by a non-conductive material 113 b such as 3MCorporation 9836 tape or 3M double-sided Transfer Adhesive 9917 (3M, St.Paul, Minn.) or equivalent. The additional layer 113 d, if used, mightbe a 3M 9917 adhesive together with the 113 b of a 9836 material. Theseconstructs may provide the effect of creating a low electrical impedancepath in the Z-axis direction (perpendicular to page for FIG. 1E andvertically/transversally for FIGS. 1F and 1G) for the electrode areas113 c, and high electrical impedance path between the electrodes in theX/Y directions. (See FIGS. 1E, 1F and 1G; coplanar with the page in FIG.1E and horizontal and perpendicular to the page in FIGS. 1F and 1G).Thus, a composite adhesive strip can ensure not only device adhering tothe patient, but also that the electrodes whether two or as shown threeelectrodes are conductively connected by conductive portions of theadhesive strip, where the combination of conductive and non-conductiveportions can then reduce signal noise and/or enhance noise freecharacteristics. Electrodes that move relative to skin can introducenoise. I.e., electrodes electrically communicative/connected to the skinvia a gel may move relative to the skin and thus introduce noise.However, with one or more conductive adhesive portions in a compositeadhesive connected to respective electrodes and then substantiallysecurely connected to the skin will keep the respective electrodessubstantially fixed relative to the skin and thereby reduce or eveneliminate electrode movement relative to the skin. Removal of suchmovement would then remove noise which would thereby provide a cleansignal that can allow for monitoring cardiac P waves which enhances thepossibility to detect arrythmias that couldn't otherwise be detected.Further description is set forth below.

In some implementations, a further optional connective and/or insulativestructure 113 d may be implemented as shown in FIG. 113d to providefurther structural and insulative separation between electrodes withconnected to a device 100 on the underside 102 thereof (see FIG. 1G).Though shown separate in FIGS. 1F and 1G, it may be contiguous with theinsulative adhesive 113 b of these views.

Some alternative implementations hereof may include a driven right legECG circuit with one or more chest only electrodes (“Driven ChestElectrode”). In addition to the electrodes used to measure a single ormultiple lead electrocardiogram signal, a device 100 may use anadditional electrode, as for example the reference electrode 110 (seeFIGS. 1A, 1C, 1D and 1G, e.g.) to reduce common mode noise. Such anelectrode may function in a manner similar to the commonly-used drivenright leg electrode, but may here be located on the patient's chestrather than on the patient's right leg but nevertheless thisthird/reference electrode may play the role of the leg electrode. Thischest electrode may thus mimic a right leg electrode and/or beconsidered a proxy driven right leg electrode. A circuit, or portion ofan overall circuit, adapted to operate in this fashion may include anumber of amplifier stages to provide gain, as well as filtering toensure circuit stability and to shape the overall frequency response.Such a circuit may be biased to control the common mode bias of theelectrocardiogram signal. This driven chest electrode implementation maybe used in conjunction with a differential or instrumentation amplifierto reduce common mode noise. In this case, the sense electrode may beused as one of the electrocardiogram electrodes. Alternatively, asingle-ended electrocardiogram amplifier may be used where thedifferential electrocardiogram signal is referenced to ground or to someother known voltage.

A circuit or sub-circuit 200 using a transistor 201 as shown in FIG. 2may be such a circuit (aka module) and may thus include as further shownin FIG. 2A, a sense electrode 202, a drive electrode 203, and anamplifier 204. Both the sense and drive electrodes 202, 203 are placedon the patient's chest such that they provide an electrical connectionto the patient. The amplifier 204 may include gain and filtering. Theamplifier output is connected to the drive electrode, the invertinginput to the sense electrode, and the non-inverting input to a biasvoltage 205. The amplifier maintains the voltage of the sense electrodeat a level close to the bias voltage. An electrocardiogram signal maythen be measured using additional electrodes. Indeed, as was the casefor the improved conductivity through use of anisotropic adhesiveportions above, here also or alternatively, the use of this thirdelectrode as a proxy for a right leg electrode (i.e., proxy driven rightleg electrode) can provide signal reception otherwise unavailable. Cleansignals may thus allow for receiving cardiac P waves which enhances thepossibility to detect arrythmias that couldn't otherwise be detected.

Further alternative descriptions of circuitry include that which isshown in FIGS. 2B and 2C; in which are shown non-limiting alternativesin which three adjacent electrodes E1, E2, and E3 may be used to pick upthe ECG signal, one of which electrodes playing the role of the distantlimb electrode of traditional ECG monitors. Because theelectrode-patient interface has an associated impedance (Re1 and Re2),current flowing through this interface will cause a difference involtage between the patient and the electrode. The circuit may use asense electrode (E1) to detect the patient voltage. Because thisexemplar circuit node has a high impedance to circuit ground (GND), verylittle current flows through the electrode interface, so that thevoltage drop between the patient and this node is minimized. The firstof these alternative, non-limiting circuits (FIG. 2B) also contains anamplifier (U1) whose low-impedance output is connected to a separatedrive electrode (E2). The amplifier uses negative feedback to controlthe drive electrode such that the patient voltage (as measured by thesense electrode E1) is equal to the bias voltage (V1). This mayeffectively maintain the patient voltage equal to the bias voltagedespite any voltage difference between the driven electrode (E2) and thepatient. This can include voltage differences caused by powerline-induced current flowing between the drive electrode and the patient(through Re2). This arrangement differs from a traditional‘driven-right-leg’ circuit in at least two ways: the driven electrode isplaced on the patient's chest (rather than the right leg), and the ECGsignal is a single-ended (not differential) measurement taken from athird electrode (E3). Because all electrodes are located on thepatient's chest, a small device placed there may contain all thenecessary electrodes for ECG measurement. One possible benefit of thesingle-ended measurement is that gain and filtering circuitry (U2 andassociated components (FIG. 2C)) necessary to condition the ECG signalprior to recording (ECG Output) requires fewer components and may beless sensitive to component tolerance matching. The examples of FIGS.2A, 2B and 2C are non-limiting examples and not intended to limit thescope of the claims hereto as other circuits with other circuit elementscan be formed by skilled artisans in view hereof and yet remain withinthe spirit and scope of claims hereof.

In many implementations, a system hereof may include other circuitryoperative together with the ECG electrodes, which may thus beaccompanied by other sensors to provide time concordant traces of: i)ECG p-, qrs-, and t-waves; ii) O2 Saturation, as measured by PulseOxymetry; and/or iii) xyz acceleration, to provide an index of physicalactivity. Such circuitry may be implemented to one or more of thefollowing electrical specifications. The overall system might in someimplementations include as much as two weeks (or more) of continuous runtime; gathering data during such time. Some implementations may beadapted to provide as many or even greater than 1000 uses. Alternativesmay include operability even after or during exposure to fluids orwetness; in some such examples being water resistant, or waterproof, orwatertight, in some cases continuing to be fully operable when fullysubmerged (in low saline water). Other implementations may include fastdata transfer, as for an example where using an HS USB for full datatransfer in less than about 90 seconds. A rechargeable battery maytypically be used.

A further alternative implementation may include an electronic “ground”:In a device hereof, mounted entirely on a flexible circuit board, theground plane function may be provided by coaxial ground leads adjacentto the signal leads. The main contribution of this type of groundingsystem may be that it may allow the device the flexibility required toconform and adhere to the skin.

For electrocardiograph; EKG or ECG, some implementations may includegreater than about 10 Meg Ohms input impedance; some implementations mayoperate with a 0.1-48 Hz bandwidth; and some with an approximate 256 HzSampling Rate; and may be implementing 12 Bit Resolution. For PPG andPulse Oximeter, operation may be with 660 and 940 nm Wavelength; about80-100 SpO2 Range; a 0.05-4.8 Hz Bandwidth; a 16 Hz Sampling Rate; and12 bit resolution. For an accelerometer: a 3-Axis Measurement may beemployed, and in some implementations using a ±2 G Range; with a 16 HzSampling Rate; and a 12 Bit Resolution.

Some summary methodologies may now be understood with relation to FIG.3, though others may be understood through and as parts of the remainderof the disclosure hereof. A flow chart 300 as in FIG. 3 may demonstratesome of the alternatives; where an initial maneuver 301 might be theapplication of the device 100 to the patient. Indeed, this might includesome one or more of the alternatives for adhesive application asdescribed here above, whether by/through use of an adhesive such as that113 of FIG. 1D, or that of FIGS. 1E, 1F and/or 1G. Then, as shown, inmoving by flow line 311, a data collection operation 302 may beimplemented. Note, this might include a continuous or substantiallycontinuous collection or an interval or periodic collection or perhapseven a one time event collection. This may depend upon the type of datato be collected and/or be dependent upon other features or alternatives,as for example whether a long term quantity of data is desired, for ECGfor example, or whether for example a relative single data point mightbe useful, as in some cases of pulse oximetry (sometimes a singlesaturation point might be of interest, as for example, if clearly toolow, though comparison data showing trending over time, may indeed bemore typical).

Several alternatives then present in FIG. 3, flow chart 300; a firstsuch might be the following of flowline 312 to the transmission of dataoperation 303, which could then involve either wireless or wired (e.g.,USB or other) data communication from the device 100 to data analysisand/or storage devices and/or systems (not separately shown in FIG. 3;could include computing devices, see e.g., FIG. 4 described below, orthe like). Options from this point also appear; however, a first suchmight include following flow line 313 to the data analysis operation 304for analyzing the data for determination of the relative health and/orfor condition diagnosis of a patient. Computing systems, e.g., acomputer (could be of many types, whether hand-held, personal ormainframe or other; see FIG. 4 and description below) could be used forthis analysis; however, it could be that sufficient intelligence mightbe incorporated within the electronics 103 of device 100 such that someanalysis might be operable on or within device 100 itself. Anon-limiting example, might be a threshold comparison, as for examplerelative to pulse oximetry where when a low (or in some examples,perhaps a high) threshold level is reached an indicator or alarm mightbe activated all on/by the electronics 103 of the device 100.

A similar such example, might be considered by the optional alternativeflow path 312 a which itself branches into parts 312 b and 312 c.Following flow path 312 a, and then, in a first example path 312 b, askip of the transmit data operation 303 can be understood wherebyanalysis 304 might be achieved without substantial data transfer. Thiscould explain on board analysis, whether as for example according to thethreshold example above, or might in some instances include moredetailed analysis depending upon how much intelligence is incorporatedon/in the electronics 103. Another view, is relative to how muchtransmission may be involved even if the transmission operation 303 isused; inasmuch as this could include at one level the transmission ofdata from the patient skin through the conductors 108, 109 and/or 110through the traces 107 to the electronics 103 for analysis there. Inother examples, of course, the transmission may include off-boarddownloading to other computing resources (e.g., FIG. 4). In some cases,such off-loading of the data may allow or provide for more sophisticatedanalysis using higher computing power resources.

Further alternatives primarily may involve data storage, both when andwhere, if used. As with intelligence, it may be that either some or nostorage or memory may be made available in/by the electronics 103on-board device 100. If some storage, whether a little or a lot, is madeavailable on device 100, then, flow path 312 a to and through path 312 cmay be used to achieve some storing of data 305. This may in many casesthen, though not necessarily be before transmission or analysis (note,for some types of data multiple paths may be taken simultaneously, inparallel though perhaps not at the same time or serially (eg., paths 312b and 312 c need not be taken totally to the exclusion of the other), sothat storage and transmission or storage and analysis may occur withoutnecessarily requiring a completion of any particular operation beforebeginning or otherwise implementing another). Thus, after (or during)storage 305, flow path 315 a may be followed for stored data which maythen be transmitted, by path 315 b to operation 303, and/or analyzed, bypath 315 c to operation 304. In such a storage example, which in manycases may also be an on-board storage example, data can be collectedthen stored in local memory and later off-loaded/transmitted to one ormore robust computing resources (e.g., FIG. 4) for analysis. Frequently,this can include long term data collection, e.g., in the manner of daysor weeks or even longer, and may thus include remote collection when apatient is away from a doctor's office or other medical facilities.Thus, data can be collected from the patient in the patient's real worldcircumstances. Then, after collection, the data can be transmitted fromits storage on device 100 back to the desired computing resource (FIG.4, e.g.), and such transmission might be wireless or wired or comecombination of both, as for example a blue tooth or WiFi connection to apersonal computer (FIG. 4 for one example) which might then communicatethe data over the internet to the designated computer for finalanalysis. Another example might include a USB connection to a computer,either to a PC or a mainframe (FIG. 4), and may be to the patientcomputer or to the doctor computer for analysis.

If little or no storage or memory is resident on device 100 (or in someexamples even where there may be a large amount of resident memoryavailable), then, relatively soon after collection, the data would needto or otherwise might desirably either or both be transmitted and thenstored, see path 313 a after operation 303, and/or transmitted andanalyzed, paths 312 and 313. If path 313 a is used, then, moretypically, the data storage may be in/on computing resources (not shownin FIG. 3, but see FIG. 4 described below) off-board (though on-boardmemory could be used as well), and then, any of paths 315 a, 315 b and315 c may be used.

A feature hereof may include an overall system including one or moredevices 100 and computing resources (see FIG. 4, for example) whetheron-board device(s) 100, or separate, as for example in personal ormobile or hand-held computing devices (generally by FIG. 4), the overallsystem then providing the ability for the physician or doctor to haveimmediate, in-office analysis and presentation of collected test data.This would in some implementations allow for on-site data analysis fromthe device without utilization of a third party for data extraction andanalysis.

Alternative implementations hereof may thus include one or more hardwareand software combinations for multiple alternative data sourceinterpretations. As noted above, a device 100 hereof includes hardwarethat monitors one or more of various physiologic parameters, thengenerates and stores the associated data representative of the monitoredparameters. Then, a system which includes hardware such as device 100and/or the parts thereof, and software and computing resources (FIG. 4,generally) for the processing thereof. The system then includes not onlythe collection of data but also interpretation and correlation of thedata.

For example, an electrocardiogram trace that reveals a ventriculararrhythmia during intense exercise may be interpreted differently thanthe same arrhythmia during a period of rest. Blood oxygen saturationlevels that vary greatly with movement can indicate conditions that maybe more serious than when at rest, inter alia. Many more combinations ofthe four physiologic parameters are possible, and the ability ofsoftware hereof to display and highlight possible problems will greatlyaid the physician in diagnosis. Thus, a system as described hereof canprovide beneficial data interpretation.

Some of the features which can assist toward this end may be subsumedwithin one or more of operations 303 and 304 of FIG. 3, wherein datacollected on a device 100 can rather simply be communicated/transmittedto computing resources (again, whether on-board device 100 or discretetherefrom as e.g., FIG. 4). For an example, when a patient having had adevice applied (operation 301) may return to a physician's office aftera test period wherein data was collected (operation 302) the device isconnected via one or more data transmission alternatives, as forexample, USB to a computer (Windows or Mac) (generally with reference toFIG. 4 and description thereof) in the office, allowing immediateanalysis by the physician while the patient waits (note, the device 100may first have been removed from the patient or might remain thereonpending transmission and analysis for determination of whether more datamay be desired). In some implementations, data analysis time may berelatively quick, at approximately 15 minutes in some implementations,and might be achieved with a user-friendly GUI (Graphic User Interface)to guide the physician through the analysis software.

The analysis/software package may be disposed to present the physicianwith results in a variety of formats. In some implementations, anoverview of the test results may be presented, either together with orin lieu of more detailed results. In either case, a summary of detectedanomalies and/or patient-triggered events may be provided, either aspart of an overview and/or as part of the more detailed presentation.Selecting individual anomalies or patient-triggered events may providedesirable flexibility to allow a physician to view additional detail,including raw data from the ECG and/or from other sensors. The packagemay also allow data to be printed and saved with annotations inindustry-standard EHR formats.

In one implementation, patient data may be analyzed with software havingthe one or more of the following specifications. Some alternativecapabilities may include: 1. Data Acquisition; i.e., loading of datafiles from device; 2. Data Formatting; i.e., formatting raw data toindustry standard file formats (whether, e.g., aECG (xml); DICOM; orSCP-ECG) (note, such data formatting may be a part of Acquisition,Storage or Analysis, or may have translation from one to another (e.g.,data might be better stored in a compact format that may needtranslation or other un-packing to analyze)); 3. Data Storage (whetherlocal, at a clinic/medical facility level or e.g., in the Cloud(optional and allows offline portable browser basedpresentation/analysis); 4. Analysis which inter alia, may include, e.g.,noise filtering (High pass/Low pass digital filtering); and/or QRS(Beat) detection (in some cases, may include Continuous Wave Transform(CWT) for speed and accuracy); and/or 5. Data/Results Presentation,whether including one or more graphical user interface(s) (GUIs) perhapsmore particularly with an overall Summary and/or General Statisticsand/or Anomaly Summary of Patient triggered event(s); presentation ofadditional levels of detail whether of Strip view(s) of anomaly data byincident (previous, next) Blood Oxygen saturation, stress correlation orthe like; and/or allowing care provider bookmarking/annotations/notes byincident and/or Print capability.

Further, on alternative combinations of hardware with proprietarysoftware packages: I) One on-device software package may be adapted tostore the measurements from the data signals acquired from one or moreof EKG/ECG (whether right leg and/or p-, qrs- and/or t-waves), or O2saturation, or xyz acceleration, in a time concordant manner, so that aphysician may access a temporal history of the measurements (say, insome examples, over a 1-2 week interval), which would provide usefulinformation on what the patient's activity level was prior to, during,and after the occurrence of a cardiac event. ii) an alternative toalternately manage the real-time transmission of the real-time measuredparameters to a nearby station or relay. And/or; iii) an off-device ECGanalysis software aimed at recognizing arrhythmias.

The software mentioned above may be industry understood softwareprovided by a 3rd party, or specially adapted for the data developed andtransmitted by and/or received from a wearable device 100 hereof.Thorough testing using standard (MIT-BIH/AHA/NST) arrhythmia databases,FDA 510(k) approvals preferred. Such software may be adapted to allowone or more of automated ECG analysis and interpretation by providingcallable functions for ECG signal processing, QRS detection andmeasurement, QRS feature extraction, classification of normal andventricular ectopic beats, heart rate measurement, measurement of PR andQT intervals, and rhythm interpretation.

In many implementations, the software may be adapted to provide and/ormay be made capable of supplying one or more of the followingmeasurements:

-   -   1. Heart Rate Min, Max and Average    -   2. QRS duration average    -   3. PR interval average    -   4. QT interval average    -   5. ST deviation average        and, may be adapted to recognize a broad range of arrhythmias        such as those set forth here:    -   1. SINUS RHYTHM    -   2. SINUS RHYTHM+IVCD    -   3. SINUS BRADYCARDIA    -   4. SINUS BRADYCARDIA+IVCD    -   5. SINUS TACHYCARDIA    -   6. PAUSE    -   7. UNCLASSIFIED RHYTHM    -   8. ARTIFACT

This first group of 8 given above are arrhythmia types that may berecognizable even if there is no discernible P wave. They are the onestypically recognized by existing products in the outpatient monitoringmarket that we propose to address.

A second set or group of arrhythmias; below, may require a discernibleand measurable P wave. Some implementations hereof may be adapted to beable to detect and recognize them, as device 100 may be able asdescribed above to detect P waves, depending of course, and for example,on whether the strength of the P wave is affected by device 100placement or patient physiology.

-   -   9. ATRIAL FIBRILLATION/FLUTTER SVR (slow)    -   10. ATRIAL FIBRILLATION/FLUTTER CVR (normal rate)    -   11. ATRIAL FIBRILLATION/FLUTTER RVR (rapid    -   12. FIRST DEGREE AV BLOCK+SINUS RHYTHM    -   13. FIRST DEGREE AV BLOCK+SINUS TACHYCARDIA    -   14. FIRST DEGREE AV BLOCK+SINUS BRADYCARDIA    -   15. SECOND DEGREE AV BLOCK    -   16. THIRD DEGREE AV BLOCK    -   17. PREMATURE ATRIAL CONTRACTION    -   18. SUPRAVENTRICULAR TACHYCARDIA    -   19. PREMATURE VENTRICULAR CONTRACTION    -   20. VENTRICULAR COUPLET    -   21. VENTRICULAR BIGEMINY    -   22. VENTRICULAR TRIGEMINY    -   23. IDIOVENTRICULAR RHYTHM    -   24. VENTRICULAR TACHYCARDIA    -   25. SLOW VENTRICULAR TACHYCARDIA

Further in alternative software implementations; some sample screenshotsare shown in FIG. 5. A first such alternative is shown in FIG. 5A, whichis an example screenshot showing ECG and Oxygen Saturation data taken byusing a patch device such as a device 100 hereof. An extremely cleansignal is shown (no filtering or smoothing has been done on this data).Distinct p-waves are also shown (3 of which are shown as an example witharrows). P wave detection can be extremely important for ECG anomalydetection. Oxygen Saturation, as measured by Pulse Oxymetry, is shown onthe bottom plot. This is data taken by the a device on the chest, and istaken in time concordance with the ECG data.

Another alternative is shown in FIG. 5B, which is an example screenshotof Analysis Software. This is a sample of ECG data taken from theMIT-BIH Arrhythmia Database, Record 205. As analyzed by the Analysissystem hereof, we see in the Event Occurrences Summary list (top, left)five (5) anomaly types (plus normal sinus rhythm). This list also showsthe number of occurrences of each anomaly, total duration of the anomalyin the complete ECG, and the percent time this anomaly occurs in thecomplete ECG. To view specific instances of each anomaly, the userdouble clicks the specific row in the Event Occurrences Summary list, asshown in FIG. 5C.

As introduced, FIG. 5C is an example screenshot showing specificinstance of Ventricular Tachycardia. The ECG plot automaticallynavigates to the specific time in the ECG waveform, and marks thebeginning and end of the event. More detailed data about this specificevent is now shown in the Occurrence Details: HR Average, HR Max, etc.for the duration of this event. To show the instances of another anomalyin this ECT, the user can click on the Premature Ventricular Contraction(PVC) row of the Event Occurrences Summary, as shown FIG. 5D.

As introduced, FIG. 5D is an example screenshot showing specificinstance of Premature Ventricular Contraction. This shows occurrences ofthe PVC. The Start Times list (middle top) shows all instances of PVCoccurrences in this ECG, and lists the start time for each occurrence.In this case, the user can click on the PVC that starts at 00:15:27 (the11^(th) occurrence). The ECG plot is automatically taken to this pointin time to show and indicate the PVC instances in the waveform. Sincethere are 3 instances of a PVC in this timeslot, all 3 occurrences aremarked.

Some further alternatives may include data transmission and/orinterpretation by local medical facilities, whether physician or doctoroffices or e.g., ICU/CCU (Intensive Care/Coronary Care Units).Accordingly, a device 100 hereof that will measure one or more of avariety of physiologic signals, possibly including electrocardiogram,photoplethysmogram, pulse oximetry and/or patient acceleration signalswill be placed on the patient's chest and held with an adhesive asdescribed herein. The device transmits the physiologic signalswirelessly or by wire (e.g., USB) to a nearby base station forinterpretation and further transmission, if desired. The wirelesstransmission may use Bluetooth, WiFi, Infrared, RFID (Radio FrequencyIDentification) or another wireless protocol. The device may be poweredby wireless induction, battery, or a combination of the two. The device100 monitors physiological signals and/or collects data representativethereof. The collected data may then be transmitted wirelessly or bywire connection, in real time, to the nearby base station. The devicemay be wirelessly powered by the base station or by battery, removingthe need for wires between the patient and the station.

Thus, some of the alternative combinations hereof may include one ormore of: 1) medical grade adhesives (from many possible sources)selected for their ability to maintain in intimate contact with the skinwithout damaging it, for several days (up to, say 10 days or two weeksin some examples), as well as operability with different types ofsensors; 2) conductive electrodes or photo-sensitive detectors able tosupply electrical signals from the skin or from the photo-response ofcutaneous or subcutaneous tissues to photo-excitation; 3) amplifiers,microprocessors and memories, capable of treating these signals andstoring them; 4) power supply for the electronics hereof with stored orwith wirelessly accessible re-chargeability; 5) flex circuits capable oftying the above elements together within a flexible strip capable ofconforming to a cutaneous region of interest.

Examples of physiological parameters that may be subject to monitoring,recordation/collection and/or analyzing may include one or more of:electrocardiograms, photo responses of photo-excited tissues for e.g.,oxygen saturation of blood; pulse rates and associated fluctuations;indications of physical activity/acceleration. One or more of these maybe used in monitoring ambulatory cardiac outpatients over several daysand nights, which could thereby provide for recording, for post-testanalysis, several days' worth of continuous ECG signals together withsimultaneous recording of O2 saturation and an index of physicalexertion. Similarly, one or more of these may be used in monitoringambulatory pulmonary outpatients over several days and nights forrecording, for post-test analysis, O2 saturation together withsimultaneous recording of an index of physical activity. Alternativelyand/or additionally, one or more of these could be used for monitoringin-patients or other patients of interest, as for example neonatals,wirelessly (or in some cases wired), whether in clinics, emergencyrooms, or ICUs, in some instances detecting the parameters of EKG, O2and/or physical exertion, but instead of storing them would transmitthem wirelessly to either a bedside monitor or a central stationmonitor, thus freeing the patient from attachment to physical wires.

An exemplary computer system or computing resources which may be usedherewith will now be described, though it should be noted that manyalternatives in computing systems and resources may be available andoperable within the reasonably foreseeable scope hereof so that thefollowing is intended in no way to be limiting of the myriad possiblecomputational alternatives properly intended within both the spirit andscope hereof.

Some of the implementations of the present invention include varioussteps. A variety of these steps may be performed by hardware componentsor may be embodied in machine-executable instructions, which may be usedto cause a general-purpose or special-purpose processor programmed withthe instructions to perform the steps. Alternatively, the steps may beperformed by a combination of hardware, software, and/or firmware. Assuch, FIG. 4 is an example of computing resources or a computer system400 with which implementations hereof may be utilized. According to thepresent example, a sample such computer system 400 may include a bus401, at least one processor 402, at least one communication port 403, amain memory 404, a removable storage media 405, a read only memory 406,and a mass storage 407. More or fewer of these elements may be used in aparticular implementation hereof.

Processor(s) 402 can be any known processor, such as, but not limitedto, an Intel® Itanium® or Itanium 2® processor(s), or AMD® Opteron® orAthlon MP® processor(s), or Motorola® lines of processors. Communicationport(s) 403 can be any of an RS-232 port for use with a modem baseddialup connection, a 10/100 Ethernet port, a Universal Serial Bus (USB)port, or a Gigabit port using copper or fiber. Communication port(s) 403may be chosen depending on a network such a Local Area Network (LAN),Wide Area Network (WAN), or any network to which the computer system 400connects or may be adapted to connect.

Main memory 404 can be Random Access Memory (RAM), or any other dynamicstorage device(s) commonly known in the art. Read only memory 406 can beany static storage device(s) such as Programmable Read Only Memory(PROM) chips for storing static information such as instructions forprocessor 402.

Mass storage 407 can be used to store information and instructions. Forexample, hard disks such as the Adaptec® family of SCSI drives, anoptical disc, an array of disks such as RAID, such as the Adaptec familyof RAID drives, or any other mass storage devices may be used.

Bus 401 communicatively couples processor(s) 402 with the other memory,storage and communication blocks. Bus 401 can be a PCI/PCI-X or SCSIbased system bus depending on the storage devices used.

Removable storage media 405 can be any kind of external hard-drives,floppy drives, IOMEGA® Zip Drives, Compact Disc-Read Only Memory(CD-ROM), Compact Disc-Re-Writable (CD-RW), Digital Video Dis-Read OnlyMemory (DVD-ROM).

The components described above are meant to exemplify some types ofpossibilities. In no way should the aforementioned examples limit thescope of the invention, as they are only exemplary embodiments.

Embodiments of the present invention relate to devices, systems,methods, media, and arrangements for monitoring and processing cardiacparameters and data, inter alia. While detailed descriptions of one ormore embodiments of the invention have been given above, variousalternatives, modifications, and equivalents will be apparent to thoseskilled in the art without varying from the spirit of the invention.Therefore, the above description should not be taken as limiting thescope of the invention, which is defined by the appended claims.

What is claimed is:
 1. A method for reducing noise in cardiac monitoringusing a wearable monitoring device having at least two electrodes forcardiac monitoring; the method comprising: applying the wearablemonitoring device externally to a subject, the subject having at least aright leg; operating circuitry adaptations comprising: operating a firstelectrode; operating a second electrode also referred to as a proxydriven-right-leg electrode mimicking a right leg electrode; the secondelectrode being the proxy driven-right-leg electrode affixed on thesubject other than on the right leg of the subject; operating a voltageor current driver operatively connected to the first and secondelectrodes to drive one or both a voltage or current to the secondelectrode; operating a reference voltage configured to be operativelyassociated with the first and second electrodes; driving by applicationof a voltage or current, to the second electrode also known as the proxydriven-right-leg electrode, maintaining the voltage of the firstelectrode at a relationship, other than a common mode voltage ofmultiple additional electrodes, to the voltage of an additionalelectrode; generating an output representative of a noise-reducedphysiological signal for cardiac monitoring.
 2. A method according toclaim 1 further comprising one or both: transmitting the data from thewearable device; or, transmitting the data from the wearable device;and, storing the data prior to one or both of transmitting or analyzingthe data.
 3. A circuit for mimicking a right leg electrode using areference electrode as proxy therefor; the circuit comprising thecombination A), B), C), D) with one or more of W), X), Y), Z): A) aconnection to a first electrocardiogram electrode; B) a connection to asecond electrocardiogram electrode; C) a connection to a referenceelectrocardiogram electrode; and, D) an amplifier; the electrodeconnections all connected to the amplifier; the amplifier maintainingthe voltage of the first electrode at a relationship, other than acommon mode voltage of multiple additional electrodes, to the voltage ofan additional electrode, a proxy driven right leg signal beingmeasurable using a reference electrode and being used in generating anoutput representative of a noise-reduced physiological signal forcardiac monitoring; the reference electrode being the proxydriven-right-leg electrode affixed on a subject other than on a rightleg of the subject; and W) a connection to a sense electrode; X) aconnection to a drive electrode; Y) a bias voltage input; and, Z) anamplifier; the electrode connections and bias voltage input connected tothe amplifier; the amplifier output connected to the drive electrode, aninverting input to the sense electrode, and a non-inverting input to abias voltage; the amplifier maintaining the voltage of the firstelectrode at a relationship, other than the common mode voltage ofmultiple additional electrodes, to the voltage of an additionalelectrode; the proxy driven right leg signal being measurable using athird electrode and being used in generating an output representative ofa noise-reduced physiological signal for cardiac monitoring; the thirdelectrode being the proxy driven-right-leg electrode affixed externallyon a subject other than on a right leg of the subject.
 4. A methodaccording to claim 1 further comprising: collecting data representativeof physiological signals; and, analyzing the data.
 5. A method accordingto claim 1 the maintaining operation further comprising one or more of:maintaining the voltage of the first electrode at a relationship equalto or approximately equal to the bias or reference or ground voltage;maintaining the voltage of the first electrode at a relationship of oneor more of a weighted sum, average, or common-mode voltage of the firstelectrode and at least one additional voltage; and, maintaining thevoltage of the first electrode at a relationship; of one or more of aweighted sum, average, or common-mode voltage of the first electrode andone or more of a number of additional electrodes equal to orapproximately equal to the bias voltage and one or more of a number ofadditional electrodes equal to or approximately equal to the biasvoltage.
 6. A method according to claim 1 wherein the at least oneadditional electrode includes one or more of a number of additionalelectrodes.
 7. A method according to claim 1 wherein the physiologicalsignal includes one or both an ECG or a photoplethysmography (PPG)signal.